In recent years, mobile communication systems conforming to the 3GPP specification are put to practical use one after another. An MBMS (Multimedia Broadcast Multicast Service) standardized in Rel. 6 of 3GPP is a technique in which a plurality of users can simultaneously share wireless resources in a base station (Node B) when the same data is transmitted to the plurality of users. This technique has a sufficient possibility of being put to practical use in the future (see Non-patent Documents 1 and 2). In this case, the wireless resources indicate transmission power, an extension code, a frequency sub-carrier, and the like. Furthermore, HSDPA (High Speed Downlink Packet Access) which has been standardized in Rel. 5 has been put to practically use as a speed-up technique for packet service of wireless downlink. In the future, when the MBMS will be put to practically use, the MBMS probably exists together with the HSDPA in a system, and is probably provided to share the same wireless resources in the base station.
In the 3GPP, a next-generation MBMS (obtained by upgrading an MBMS in Rel. 6) and next-generation HSDPA (obtained by upgrading HSDPA in Rel. 5) are being standardized. These techniques will probably coexist in the system, and will be probably provided to share the same wireless resources in the base station.
A control unit MAC (Medium Access Control) which controls communication of data (to be referred to as “MBMS data” hereinafter) transmitted by using a transport channel for MBMS and MAC which controls communication of data (to be referred to as “HSDPA data” hereinafter) transmitted by using a transport channel for HSDPA are independent as a MAC-m and a MAC-hs, respectively. The MAC-m is in a base station control apparatus (RNC), and the MAC-hs is in a base station. For this reason, sharing of wireless resources in the base station between the MBMS and the HSDPA can be realized as follows.
Of all amounts of wireless resource which can be used by base stations, an amount of wireless resource which can be used in MBMS data and an amount of wireless resource which can be used in HSDPA data are set in advance. When an MBMS transmission request is received from a core network, a control unit RRC (Radio Resource Control) which performs wireless resource management or control between a mobile station (UE) and the base station collects reception requests from mobile stations being under the control of a base station to which the MBMS data is to be transmitted. In response to the reception request, the control unit RRC determines whether the MBMS data can be transmitted in consideration of a predetermined amount of wireless resource which can be used in MBMS data. When the MBMS data can be transmitted, transmission of the MBMS data is determined.
A MAC-m in the base station control apparatus controls communication of MBMS data depending on a priority or QoS in the range of wireless resource in the MBMS data set by the RRC in advance. On the other hand, when the HSDPA receives an HSDPA transmission/reception request from a core network or a mobile station, the RRC determines whether HSDPA data can be transmitted and received in consideration of a predetermined amount of wireless resource which can be used in the HSDPA data. When the HSDPA data can be transmitted and received, transmission and reception of the HSDPA data is determined.
MAC-hs in the base station controls communication of data depending on a priority of data or a CQI (Channel Quality Indicator) of each mobile station in the range of the wireless resources for HSDPA set by the RRC in advance.
In general, wireless resource information used by each data is transmitted from the RRC to the MAC-m and the MAC-hs. However, the wireless resource information is not transmitted to a MAC which does not correspond to the data. More specifically, the wireless resource information used by the HSDPA data is not transmitted to the MAC-m, and the wireless resource information used by the MBMS data is not transmitted to the MAC-hs. Therefore, in this method, the MAC-m and MAC-hs cannot recognize amounts of wireless resource used by data which do not correspond to the MAC-m and the MAC-hs, respectively. During the communication, the wireless resources for MBMS data cannot be allocated to the HSDPA data. In contrast to this, the wireless resources for HSDPA data cannot be also allocated to the MBMS data. For this reason, as shown in FIG. 1, unused wireless resources may be generated. In FIG. 1, a portion with vertical lines denotes a wireless resource used in the HSDPA data, a blank portion denotes a wireless resource used by the MBMS data, and a portion with dotted lines denotes an unused wireless resource.
The MAC-m and the MAC-hs transmit wireless resource information used in data handled by the MAC-m and the MAC-hs to each other, so that the following scheduling can be realized. Of all the amounts of wireless resource which can be used by base stations, an amount of wireless resource which can be used in the MBMS data is set in advance. When the RRC receives an MBMS transmission request from the core network, the RRC permits the MBMS transmission request when it is determined that the MBMS can be transmitted in the wireless resource for the predetermined MBMS data.
The MAC-m in the base station control apparatus controls data communication depending on a priority or QoS between MBMS data in the range of the wireless resource for MBMS data set by the RRC in advance. On the other hand, the MAC-m notifies the MAC-hs in the base station of an amount of wireless resource actually used by the MBMS data. The MAC-hs controls data communication depending on CQI or a priority of each UE by using the remaining wireless resources which can be used in the base station.
In this manner, the MAC-m notifies the MAC-hs of the amount of wireless resource actually used by the MBMS data to make it possible to allocate all the remaining amount of wireless resource which can be used in the base station. In this manner, a usage rate of the wireless resources which can be used in the base station can be increased. In contrast to this, the MAC-hs notifies the MAC-m of the amount of wireless resource used by the HSDPA data to make it possible to increase a usage rate of the wireless resources which can be used in the base station. In FIG. 2, a portion with vertical lines denotes a wireless resource used in the HSDPA data, and a blank portion denotes a wireless resource used by the MBMS data.
There is a dispersion call control method in which a base station controller changes a transmission power of a base station allocated to channels of HSDPA data and dedicated audio data in response to the reception of a usage rate information signal (for example, see Patent Document 1).    [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-166236    [Non-patent Document 1] 3GPP TS 25.321 V6.3.0 (2004-12) 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Medium Access Control (MAC) protocol specification    [Non-patent Document 2] 3GPP TS 25.346 V6.2.0 (2004-09) 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Introduction of the Multimedia Broadcast Multicast Service (MBMS) in the Radio Access Network (RAN); Stage 2